it’s non turbo and it’s not original motor .... it’s been running great have used it off and on for the 6 months I owned it no more than a hour or 2 at a time ....last night I pushed snow with it for 6hrs or so then it started missing and blowing a little blue / white smoke ....I found he air filter had a lot of snow in it so I blew it out and it ran great again for about 30 mins then started missing and smoking again but this time wasn’t the filter.... after I got it back to my shop I notice oil around where exhaust manifold meets engine block .... any idea the problem ?